This relates generally to electronic devices, and, more particularly, to electronic devices with displays.
Electronic devices such as computers, cellular telephones, televisions, and other equipment often have displays. For example, an electronic device may have a liquid crystal display that includes upper and lower polarizer layers, a thin-film transistor layer and a color filter layer that are interposed between the upper and lower polarizer layers, and a layer of liquid crystal material interposed between the thin-film transistor layer and color filter layer.
To prevent damage to the display, a protective layer of cover glass may be provided. In displays with touch sensors, a touch sensor panel may be attached to the underside of the display cover glass.
To reduce unwanted reflections within a display, layers of material in the display such as the lower surface of the touch sensor panel and the upper surface of the upper polarizer are sometime coated with antireflection coatings. These coatings are formed using a wet coating process and are therefore referred to as wet antireflection coatings. During formation of a wet antireflection coating on a substrate, liquid coating materials are deposited on a surface of a substrate. By drying the liquid coating materials, clear antireflection films can be formed.
Some displays use a full lamination process in which the touch sensor panel is laminated to underlying layers such as the upper polarizer layer using adhesive. Fully laminated displays may exhibit satisfactory display performance, but can be difficult or impossible to rework in the event that a touch sensor component requires replacement during manufacturing.
To allow a display to be reworked, the touch sensor panel in a display may be separated from the upper polarizer by an air gap. During manufacturing, devices that contain defective touch sensor parts can be reworked. Wet antireflection layers may be formed on the lower surface of the touch sensor panel and on the upper surface of the upper polarizer on opposing sides of the air gap. If care is not taken, however, pressure from a user's finger on the cover glass on the front of a display can lead to undesirable visible artifacts such as Newton's rings. If, for example, a user presses inwardly on the cover glass on a display, the cover glass may flex inwardly towards the upper polarizer. With sufficient pressure, the inner surface of the cover glass or the inner surface of a touch panel mounted on the cover glass may bridge the air gap and come into contact with the upper surface of the polarizer, leading to the production of unsightly Newton's rings on the display.
It would therefore be desirable to be able to provide improved displays for electronic devices.